Recently, many new functions for use in mobile stations have been developed. These include, for example, functions for downloading software containing application programs written in Java (registered trademark) programming language (the application program will be referred to as ‘Java-APP’, and the software will be referred to as ‘Java-AP software’ hereinafter), through communication networks, and also functions for running Java-APPs.
Behavior of applications, which are groups of functions realized in mobile stations when Java-APPs are run (the application will be referred to as ‘Java-AP’ hereinafter) is generally subject to greater restriction than that of native application programs, which application programs are installed in mobile stations prior to distribution to users; and include email communication applications, and the like. (For example, refer to Japanese patent laid-open No. 10-254783.)
Specifically, Java-APs are generally not permitted to access confidential data, such as telephone directory data stored in a mobile station. The rationale for restricting the behavior of Java-APs in this way is to prevent leakage or falsification of confidential data by Java-APs which are realized by Java-APPs containing either malicious code or code errors.
However, imposing strict behavior restriction on all Java-APs makes it impossible to meet demands of users who wish to use a variety of new and useful functions of Java-APs. Similarly, such comprehensive restriction also makes it impossible for Contents Providers (referred to as ‘CPs’ hereinafter) to provide to users Java-APPs which are capable of providing a variety of such functions.
In a case that reasonable security (reliability) of such Java-APPs can be assured, it is likely that users would not object to Java-APs being able to access personal data stored in a mobile station in which they are run. Moreover, it would be desirable for CPs to be able to provide users with more functional Java-APPs than is currently the case, and which can provide various functions in utilizing personal data stored in mobile stations.
To meet the demands explained above, different systems have been proposed, such as the one outlined below.
In this example, a carrier which provides communication services to users of mobile stations grants rights of behavior with fewer restrictions to Java-APs, than those that are normally applied; and the carrier informs the mobile stations of the kind of rights that have been granted to the Java-APs. The carrier would normally be one that is considered to be reliable in terms of security by users; thus, in this explanation the expression ‘reliable agency’ is used. In the system in question, restriction of behavior of Java-APs is controlled at a mobile station on the basis of rights informed to the mobile station by the reliable agency.
However, this system suffers from a problem. Namely, during use, the reliable agency informs mobile stations of those rights of behavior for which restrictions are relaxed for Java-APPs operable in the mobile stations. Then, the mobile stations accordingly set restrictions for the behavior of the Java-APs. However, it may become necessary for the reliable agency to modify information about such behavior rights. This would be the case, say, in a situation where it is retrospectively realized that a behavior right relaxation of a Java-AP is having a detrimental effect on users. Such a case could include that in which a Java-AP reads out personal data stored in a mobile station memory and transmits the data to an external device without the consent of the owner. In this case, it would be necessary for the reliable agency to immediately modify allowable behavior of the Java-AP. Simply put, there will be occasions on which to ensure data security it becomes necessary to (rapidly) modify rights of behavior granted by a reliable agency to a Java-AP.
In consideration of such problems, the present invention has been made to provide a system which enables modifications of rights, which have been granted to communication devices such as mobile stations, to be reflected as restrictions of behaviors in the communication devices.